The present invention relates generally to couplings, and more particularly to couplings for electrical or fluid and electrical lines between adjacent coupled vehicles such as between the tractor and trailer portions of a road vehicle or between adjacent railway cars in a train. Therefore, it will be understood that although the invention is discussed primarily with regard to connections between the tractor and trailer or tandem trailers of a road vehicle, the invention is nevertheless applicable to other adjacent vehicles wherein electrical and/or fluid connections must be maintained therebetween.
In modern tractor-trailer combinations such as commonly utilized for over-the-road freight hauling, air lines and electrical lines must be connected between the tractor and the trailer to provide motive power for operation of the trailer brakes and electrical lights, respectively. Generally, and particularly in the American trucking industry, there are provided two air lines and one multiple conductor electrical line which typically must be independently coupled from the tractor to the trailer.
A tractor commonly picks up a trailer by backing up to it to engage the king pin whereby the tractor and trailer are mechanically hitched. Thereafter, the couplings at the free ends of the air lines and electrical lines are manually retrieved from a hanging position on the back of the tractor cab and are connected to respective couplings on the trailer. The conventional air line couplings are known as glad hand couplings and are operable somewhat in the manner of rotary bayonet type locks. The multiple conductor electrical line is connected by means of a conventional plug and socket arrangement. The socket typically comprises a recessed opening with a spring loaded hinged cover and a plurality of electrically conductive pins recessed in the socket opening. The plug member comprises an elongated body which is dimensioned to be interfitted within the socket opening and having respective pin receiving openings or sockets in the free end thereof for engagement with the electrically conductive pins of the socket member.
The coupling of the individual air lines and the electrical line commonly must be done independently of each other and often with some difficulty. For example, the conventional electrical plug and socket connectors, as above characterized, are frequently exposed to the elements and over time the electrically conductive pins and their mating elements will become corroded thereby making the coupling and decoupling process far more difficult than it need be and in some situations also dangerous. Further, since the electrical connectors typically must be prealigned manually for engagement, the initial alignment may vary considerably, thus causing undue wear on the electrical coupling elements during engagement and greater difficulty in engaging the elements for operation. Still further, the hanging weight of the cable connected to the plug causes misalignment during disconnection of the plug from the socket, thus resulting in further loosening and bending of the connector pins.
Often the pins of the socket element may become so badly deformed and/or misaligned from mishandling during connecting and disconnecting, and/or corroded from exposure to the elements, that it ultimately becomes very difficult if not impossible to engage and disengage the electrical plug and socket elements quickly and safely. The result may be that a plug often may not be fully engaged within its socket to the point of locking engagement or may be extremely difficult to disengage from the socket due to pin and/or receptacle corrosion. The increased difficulty of manual connector disengagement leads to further damage to the plug and socket members as the operator may well attempt to rock the plug member laterally or twist it about its axis while pulling on it to disengage the connector members. If the connectors suddenly and unexpected disengage under extreme pulling effort, the operator may well suffer injury to his arm. There have been numerous reports of injured elbows, specifically when an operator, in an attempt to disengage electrical connectors on the truck, pulls so hard that upon sudden release of the plug his elbow strikes the adjacent trailer. The confining space between tractor and trailer often is another factor which promotes undue electrical connector component wear as the limited space prevents the operator from standing directly behind the electrical connector to pull it straight out of the socket.
For the above and other reasons, practitioners in the art have constantly sought improvements in electrical and electrical/air hybrid connectors for connecting adjacent vehicles in a manner that will minimize undue connector component wear and risk of injury to the operator.
Among the patented art pertaining to such connectors are the following: U.S. Pat. Nos. 4,624,472; 4,475,751; 4,366,965; 4,092,034; 3,954,476; and 3,888,513. In particular, I am one of the inventors named in U.S. Pat. No. 4,624,472. That patent discloses various embodiments of a hybrid connector, including embodiments wherein a pivotal lever carried by the socket element is operable to draw the plug and socket members into operative engagement and to lock same in operative engagement by means of an over-center locking action.